Reconstruction of an extensive midfacial defect using additive manufacturing techniques

Abstract

Malignant peripheral nerve sheath tumours are extremely rare tumours arising in peripheral nerves. Only 17 cases involving the trigeminal nerve have ever been reported. These tumours have a very poor prognosis and very high rates of recurrence and metastases. Their recommended treatment involves complete tumour resection followed by radiation. This can be problematic in the head and neck region. We present a clinical case involving a 33 year old female patient presenting with a slow growing exophytic mass of the anterior maxilla. Incisional biopsy and subsequent histological examination revealed a diagnosis of a malignant peripheral nerve sheath tumour. Surgical resection involved a complete maxillectomy, rhinectomy, and resection of the upper lip and aspects of the left and right cheeks. Reconstruction of the subsequent defect incorporated the placement of 4 zygomatic oncology implants to aid in retention of a facial prosthesis. These implants, however, were subsequently lost so it was decided to manufacture an anatomical model of the hard tissues via 3D printing. This model was used to design and manufacture a titanium frame (customised implant) for the patient, which was then fixated and secured intra-operatively with 21 cortical screws. A maxillary denture and silicone facial prosthesis were also made to fit onto this frame. This is the first known case where additive manufacturing, via the use of rapid prototyping and 3D printing, was employed to manufacture a facial prosthesis.